<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>Bootstrap 101 Template</title>
    <!-- Bootstrap -->
    <link href="bootstrap/css/bootstrap.min.css" rel="stylesheet">

    <!-- HTML5 shim and Respond.js for IE8 support of HTML5 elements and media queries -->
    <!-- WARNING: Respond.js doesn't work if you view the page via file:// -->
    <!--[if lt IE 9]>
    <script src="https://oss.maxcdn.com/html5shiv/3.7.2/html5shiv.min.js"></script>
    <script src="https://oss.maxcdn.com/respond/1.4.2/respond.min.js"></script>
    <![endif]-->
</head>
<style>
    * {
        box-sizing: border-box;
    }
    .row div {
        border: 1px solid black;
    }
</style>
<body>
    <div class="container">
        <div class="row">
            <div class="col-md-3 col-sm-4 col-xs-6">
                <div class="row">
                    <div class="col-md-6">1</div>
                    <div class="col-md-6">2</div>
                </div>
            </div>
            <div class="col-md-3 col-sm-4 col-xs-6">2</div>
            <div class="col-md-3 col-sm-4 col-xs-6">3</div>
            <div class="col-md-3 col-sm-4 col-xs-6">4</div>
        </div>
    </div>

<!-- jQuery (necessary for Bootstrap's JavaScript plugins) -->
<script src="http://code.jquery.com/jquery-1.11.2.min.js"></script>
<!-- Include all compiled plugins (below), or include individual files as needed -->
<script src="bootstrap/js/bootstrap.min.js"></script>
</body>
</html>